1. Field of Invention
The present invention relates to portable heating/cooling systems for effecting a temperature change of beverages to be installed on vehicles with an abundance of compressed air and/or with an internal combustion engine.
2. Description of the Prior Art
The contemporary concept of portable beverage/food cooling/heating systems falls into five groups which are based on the utilized source of the primary energy. These groups are: chemical reactions, conventional refrigeration, absorption, electricity and compressed air.
The four first-mentioned features were discussed in U.S. Pat. No. 5,331,817. It was then suggested that the fifth feature, compressed air, as a feed for the vortex tube creates a saving and an economically acceptable alternative for the above mentioned sources of energy. In accordance with this suggestion, a vortex tube based beverage/food cooling/heating design was introduced.
In a vortex tube, as it is generally known, initial compressed gas flow is transformed into two separate currents of different energy (a cold fraction and a hot fraction) leaving the vortex tube separately under pressure which is less then the inlet pressure but at a pressure still above atmospheric.
A vortex tube comprises a slender tube with a diaphragm closing one end of the tube provided with a hole in the center of the diaphragm for discharge of the cold fraction, one or more tangential inlet nozzles piercing the tube just inside of the diaphragm, and a controlled hot fraction discharge opening such as a throttle valve or any other restrictive body at the far end or the other end of the slender tube.
Even today, the full theory of the vortex tube, explaining all its features, has not yet been created or established. However, the principal mechanism of the vortex phenomenon can be described in the following manner. An expanding gas after passing the tangential nozzle develops into a high speed rotating body, a vortex. The gas in the vortex is cooled because part of its total energy converts into kinetic energy. An angular velocity in the vortex is low at the periphery zone and very high toward the center zone. Friction between the central and periphery zones reduces all of the gas to the same angular velocity as is in a solid body. This causes the inner layers to slow down and the outer layers to speed up. As a result, the inner layers lose part of their kinetic energy and their total temperature decreases. The periphery layers receive the energy from the internal layers. This energy converts to heat through friction in the `hot` end of the tube.
Having a vortex tube as a cooling/heating means, the design disclosed in the U.S. Pat. No. 5,331,817 requires, however, an incorporation into the beverage can of a canister containing a gas compressed to 300-700 psi. to be used as a vortex tube feedstock. Such requirement generally makes the system dependable on the outer source of the compressed gas let alone a user's necessity to operate a pressure vessel.
It therefore an object of this invention to develop the vortex tube based beverage cooling/heating system for the vehicles, in particular, with a vortex tube's feedstock appearing as an outcome of the vehicle's normal performance.
Generally, there are two sources of the airflow available on contemporary vehicles during its normal performance: a compressed air supplying by an `onboard` compressor in order to operate a brake system and/or a vacuumed air running through a combustion engine's intake manifold.
At this point, a vortex tube design as set forth in U.S. Pat. No. 5,327,728 to Tunkel and a vacuum vortex tube as set forth in U.S. Pat. No. 5,561,982 to Tunkel and Krasovitski are particularly useful in connection with this invention.
The latest of those patents is concerned with a novel method of energy separation and utilization of such energy separated in the vortex tube which operates with a pressure not exceeding atmospheric pressure. This method is to be carried out with a source of vacuum, a vortex tube and at least one heat exchanger. Accordingly, the vortex tube's nozzles are connected with an inlet gas flow having a pressure not exceeding atmospheric pressure, and the vortex tube's diaphragm with the hole for discharging the cold stream is connected through a heat exchanger provided to utilize a cold duty with the source of vacuum and, accordingly, the vortex tube's throttle valve or any other restrictive body for discharging of the hot stream at the opposite end of the slender tube is connected through the heat exchanger provided to utilize a hot duty with the source of vacuum.